The present invention relates to a horn speaker and more particularly relates to a horn speaker having a cooling device for cooling a moving voice coil.
A conventional loud speaker, use in a siren for a ship or the like, is required to be a type having a possibly larger voice output. In order to obtain this effect a powerful permanent magnet is used in a horn-type speaker to obtain a good electro-acoustic transducing efficiency, and a larger voice current is adapted to be input.
However, since a moving voice coil is positioned in narrow air gap between the two magnetic poles of the permanent magnet in order to obtain a strong magnetic field, its cooling effect is bad, and further, a much thicker coil cannot be used in order to reduce the mass of the vibrating parts.
Therefore, when an excessive input is applied to the speaker or it is used continuously for a long period of time, the moving voice coil is often broken by overheating.